Valve apparatus

ABSTRACT

Valve apparatus for converting a direct water drain valve into an indirect water drain valve, the direct water drain valve having at least one drain conduit, the apparatus including: a part having an inner volume and a fluid transfer aperture for fluid to enter the inner volume, the part being arranged to be connected, directly or indirectly, to the direct water drain valve so as to convert at least some of the inner volume into a substantially fluid-tight passageway between the fluid transfer aperture and the at least one drain conduit of the direct water drain valve.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.12/605,473, filed Oc. 26, 2009 and is based on, and claims priorityfrom, British Application Number 0821151.8, filed Nov. 19, 2008, thedisclosure of which is hereby incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION

Vehicles such as aeroplanes require fuel tanks to store fuel for use inthe vehicle's propulsion system. A known problem that can occur in anaircraft's fuel tank is that water builds up in the tank. For example,water vapour may enter a vent of a fuel tank and as the altitude of theaircraft increases and the temperature decreases the water vapourcondenses within the tank and, due to water being denser than aviationfuel, settles at the bottom of the tank.

A known way of removing water from a fuel tank is to provide one or morevalves to enable water to be drained from the tank upon activation of avalve. Different types of valve are used for this purpose. A directdrain valve drains water from an area adjacent the valve. An indirectdrain valve includes a tube or duct, one end of which is connected tothe valve conduit and the other is positioned at a remote location, suchthat water from the remote location can be drawn through the indirectdrain valve. These two types of valve are structurally different to oneanother.

It is desirable to place a water drain valve at the lowest area or areasof the fuel tank. Where it is possible to do so, a direct water drainvalve will generally be provided. However, where it is not possible todo so, for example because there is insufficient room to place a valveor from a structural perspective it is not desirable to cut a hole inthe tank for a valve at that position, as may be the case with aircraftwings, an indirect water drain valve will be provided in the nearvicinity and a tube will connect the indirect water drain valve to thedrainage area. Thus, it will be appreciated that in some cases it isnecessary to use two different types of valve within a single aircraft,or even within a single fuel tank. Furthermore, it will be appreciatedthat a fuel tank can be made from a number of different materials. Inorder to provide a valve in the body of a fuel tank, the outer surfaceof the fuel tank generally has a recess formed in it. The recesscorresponds in shape to a flange around the base of a valve. In somecases, to prevent rotation of the valve relative to the body, a holewill be drilled in a face of the recess for receiving a correspondingprojection on the valve. For some materials, such as metal, it isrelatively simple to form the hole within the recessed part forreceiving the projection. However, when a fuel tank is made of amaterial such as carbon composite it can be difficult to machine thehole due to the size thereof.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedvalve apparatus for converting a direct water drain valve into anindirect water drain valve, the direct water drain valve having at leastone drain conduit, the valve apparatus including a first element havingan inner volume and a fluid transfer aperture for fluid to enter theinner volume, the valve apparatus being arranged to be coupled to thedirect water drain valve such that at least some of the inner volumeforms a substantially fluid-tight passageway between the fluid transferaperture and the at least one drain conduit of the direct water drainvalve. Therefore the valve apparatus according to the first aspect ofthe invention enables an existing direct drain valve to be convertedinto an indirect drain valve. The apparatus includes a first element andis arranged to be coupled to the existing direct drain valve body so asto create a substantially fluid tight passage way between a fluidtransfer aperture through the first element and a drain conduit of thevalve. The passageway includes at least some of the inner volume of thefirst element. Thus, because a substantially fluid tight passage way isformed between the fluid transfer aperture and drain conduit, any fluidentering the inner volume of the first element through the fluidtransfer aperture can be drawn or forced to exit the valve through thedrain conduit.

The apparatus may further include a connector for fixing the directwater drain valve to a structure, the connector being arranged tointerface with the first element in a substantially fluid tight manner.Thus the connector which may be used to connect the valve body to a fueltank can also be used to create a seal between the first element and thedrain conduit. The connector may comprise a threaded nut having a slotin an axial face arranged to receive a portion of the first element in afluid-tight configuration.

The valve apparatus may further include a seal arranged to provide asubstantially fluid-tight seal between the fluid transfer aperture andan external duct. Thus fluid located adjacent the exterior of the firstelement can, in some embodiments, be prevented from entering the innervolume by locating a tube in the fluid transfer aperture of the firstelement.

The fluid transfer aperture may be provided through a side wall of thefirst element. This results in less pressure needing to be applied to afluid, from above, to force it up to a height whereby it can enter thefluid transfer aperture.

The valve apparatus may include orientation means for controlling theorientation of the first element relative to the valve body. Thisenables the first element to be set in a particular orientation and theorientation means limits further rotation of the first element relativeto the valve body. The orientation means may comprise an interlock or afriction inducing member between the first element and valve.

The first element may be a cap arranged to substantially enclose atleast a closest opening of the at least one drain conduit. This has theadvantage of enabling a closest opening of the at least one drainconduit to be enclosed by the cap and thus limit fluid entering the capvia the fluid transfer aperture from mixing with fluid from outside thecap.

According to a second aspect of the present invention, there is provideda water drain valve for enabling fluid to be drained from a fluidcontaining vessel, the valve including: a body arranged to extendthrough an outer wall of a fluid containing vessel the body having aconduit for providing an outlet from the fluid vessel; and valveapparatus including a first element having a fluid volume and a fluidtransfer aperture for fluid to enter the fluid volume and being arrangedto be coupled to the valve body such that at least some of the innervolume forms a substantially fluid-tight passageway between the fluidtransfer aperture and the conduit. Therefore the water drain valveaccording to the second aspect of the invention provides an indirectdrain valve including valve apparatus arranged to be coupled to a directdrain valve body. Due to the substantially fluid tight passage way thatis created between the fluid transfer aperture and drain conduit, anyfluid entering the inner volume of the part through the fluid transferaperture can be drawn or forced to exit the valve through the drainconduit.

The valve apparatus may further comprise a connector for fixing thevalve body to the outer wall of the fluid containing vessel, theconnector being arranged to interface with the first element in asubstantially fluid-tight manner. Thus the connector which may be usedto connect the valve body to a fuel tank can also be used to create aseal between the first element and the drain conduit. The connector mayinclude a threaded nut for securing the body to the dividing structure,the threaded nut having a slot or groove in an axial face thereofarranged to receive a portion of the first element in a fluid-tightconfiguration.

The first element may be configured such that the fluid transferaperture is adjacent a general plane of the outer wall of the fluidcontaining vessel. This results in less pressure needing to be appliedto a fluid, from above, to force it up to a height whereby it can enterthe fluid transfer aperture.

The first element may be removably connectable to another part of thevalve.

The valve body may include a non-circular or non-disc-shaped radialflange arranged to limit rotation between the body and the outer wall ofthe fluid containing vessel. Thus, the shape of the flange can preventrotation between the valve body and, for example, a fuel tank body. Theflange is oval in shape when viewed sectionally through a plane parallelto a general plane of the dividing structure at the location where thevalve body is arranged to be provided. Thus, a corresponding recess inan outside face of, for example, a fuel tank body does not contain sharpfeatures due to the oval shape of the flange.

The first element may be attachable to another part of the water drainvalve in one of a plurality of orientations and a rotation limiter isprovided to limit rotation therebetween. This enables the first elementto be set in a particular orientation and the rotation limiter limitsfurther rotation of the first element relative to the valve body.

The first element may be a cap arranged to substantially enclose anopening of the at least one drain conduit. This has the advantage ofenabling an opening of the at least one drain conduit to be enclosed bythe cap and thus prevent fluid entering the cap via the fluid transferaperture from mixing with fluid from outside the cap.

According to a third aspect of the present invention, there is provideddevice arranged to be attached to a structure, the structure having arecess formed in a surface thereof providing a recessed surface, and anaperture formed through the recessed surface, the device including abody arranged to be received in the aperture and a non-circular flangearranged to be received in the recess such that the non-circularconfiguration of the flange in combination with the recess limitsrotation between the device and the structure. Thus the device cannotrotate freely about the structure because the flange is non-circular androtation causes a part of the flange to contact a sidewall of the recessso as to prevent further rotation in that direction. Part of theperimeter of the flange is located further from the longitudinal axis ofthe body than another part. Thus, providing the recess has a perimeterwall having at least one part which is at a distance, from thelongitudinal axis of the body, greater than the shortest distancebetween the longitudinal axis of the body and the flange and less thanthe largest distance between the longitudinal axis of the body and theflange, it will result in rotation of the device being restricted. Theflange may have an oval shaped perimeter.

The device may comprise a water drain valve according to any of claims 9to 17.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1 a shows a side view of a known indirect water drain valve;

FIG. 1 b shows a side elevated view of a known direct water drain valve;

FIG. 2 a shows a perspective view of a direct water drain valveaccording to an embodiment of the invention;

FIG. 2 b shows a plan view of the valve of FIG. 2 a;

FIG. 2 c shows a perspective view of the valve of FIG. 2 a showing a nutbeing connected to the valve body;

FIG. 3 a shows a perspective view of valve apparatus according to anembodiment of the invention;

FIG. 3 b shows a perspective view of the underneath of the valveapparatus of FIG. 3 a;

FIG. 4 shows a part of the valve apparatus according to an embodiment ofthe present invention;

FIG. 5 is a cross-sectional view of an indirect water drain valveaccording to an embodiment of the invention connected to a fuel tankbase; and

FIGS. 6 a to 6 c show a front view, side view and plan view,respectively, of a device according to a further embodiment of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1 a and 1 b, two types of known clamped-type valvesare shown. FIG. 1 a shows a side view of an indirect water drain valve.It is called an indirect water drain valve because the water to bedrained is drawn through a tube 110 from a remote location. The indirectwater drain valve 100 comprises a generally cylindrical body 102 havinga flange 104 disposed at a first end thereof and a threaded neck at anopposing second end to which a nut 108 may be attached to connect thetube 110 to the second end of the body 102. The valve 100 furtherincludes a larger nut 106 arranged to engage with a threaded lower areaof the body 102.

In use, the body 102 is pushed through a hole in a face of the fueltank, corresponding in size and shape to the circumference of the body102, until the flange 104 is received within a corresponding recessformed in the outer face of the fuel tank at a location corresponding tothe hole. A projection 112 on the flange lies within a correspondinghole in the recessed area of the fuel tank to prevent rotation of thebody relative to the tank. The nut 106 may then be passed over thesecond end of the body 102 and engaged with the threaded part of thebody, so as to retain the valve 100 against the fuel tank. The tube 110may then be attached the second end of the body 102 using nut 108.

When a user, such as an aeroplane maintenance engineer, wishes to drainfuel from the area at the free opening of the tube 110 the valvemechanism is operated to open the valve and the pressure applied to thewater by the aviation fuel that lays on top of the layer of water causesthe water to exit the tank through the tube 110 and out through aconduit within the valve 100. The internal valve mechanism (not shown)comprises a conduit between the first end and second end which isblocked when the valve is in a closed configuration. The valve may bemoved to an open configuration by pressing an actuator and in this statewater may pass from the pipe 110 to the outside of the fuel tank. Forwater to be drainable from the fuel tank, via the open valve, the fueltank must generally contain a reasonable amount of aviation fuel. Theweight of the aviation fuel above the layer of water applies downwardpressure to the layer of water to cause the water to be forced to exitvia the open valve. It will be understood that the configuration of thefuel tank and the position of the indirect water drain valve within thetank affects how much fuel the fuel tank must contain to enable water tobe drained from it. In some cases, it may be necessary for a fuel tankto contain several hundred litres of fuel to provide pressure on a layerof water thereunder such that the water can be drained through anindirect water drain valve.

FIG. 1 b shows a direct water drain valve. It is known as a direct waterdrain valve because it drains water from an area adjacent the valve,without the requirement for a tube. The direct water drain valve 150comprises a generally cylindrical body 152 having a drain hole 164 forproviding passageway for water in the tank to exit the tank when thevalve is operated. As with the indirect drain valve 100, the directdrain valve 150 includes a flange 154 having a projection 162 and a nut156 for securing the valve to the fuel tank base.

FIG. 2 a shows a direct water drain valve 200 according to an embodimentof the present invention. In this example the valve 200 is aclamped-type valve but may in other embodiments be another type ofvalve, such as a bolted-type valve. The direct water drain valve 200comprises a generally cylindrical body 202 having an uppercircumferential wall 212 connected to a lower circumferential wall 210by a shoulder portion 214. The lower circumferential wall has a largerdiameter than the upper circumferential wall and has a threaded area(not shown) at an area adjacent the shoulder 214. However, it will beappreciated that the valve body 202 need not include the shoulder anddifferent diameter body portions. The valve body 202 can be of anysuitable shape, for example cylindrical, rectangular, triangular or thelike. When the body has a plurality of sides it is preferable that theareas where the side meet, i.e. corners, have rounded edges such thatthe corresponding hole in the fuel tank body does not have sharpcorners/edges. It will be appreciated that if the body isnon-cylindrical, it is possible to have a cylindrical flange as the bodyitself will oppose rotation thereof relative to the fuel tank.

One or more drain apertures 208 are formed through the valve body 202 toprovide fluid communication between an internal conduit (not shown) anarea outside the valve body 202. In the illustrated embodiment there isa plurality of drain apertures 208 and these are provided through theupper circumferential wall 212 at a lower part thereof, adjacent theshoulder 214. A part of a valve aperture is formed through the curvedexterior of the shoulder 214, such that, in use, the lowest part ofvalve aperture is substantially level with the top of the lowercircumferential wall. However, in other embodiments the valveaperture(s) 208 may be provided at different locations on the valvebody, as will be apparent to one skilled in the art.

The valve body 202 has a first end defined by the distal end of theupper circumferential wall relative to the shoulder and a second enddefining a circumferential flange 204. The flange 204 has a peripheralwall 222 and a circular groove 218 formed into the upper axial surface223. The groove 223 is arranged to receive an 0-ring sealing element toprovide a seal between the upper axial face 223 and the opposingrecessed face of a fuel tank. It will be appreciated that in someembodiments the flange 204 may be a solid portion not having the groove223. The valve body 202, in the illustrated embodiment, terminates atthe first end with a top face 220 from which extends a concentric boss216. The boss 216 includes a concentric hole which in combination withthe boss 216 provides a means by which a cap can be attached to thevalve body 202 by a mechanical fixing means, such as a screw. In someembodiments the boss 216 and hole are not provided.

In the illustrated embodiment a plurality of projections 206 areprovided that project radially from the upper circumferential wall 210near the top face 220. The projections 206 provided on the outer face ofthe valve body 202 are arranged to restrict the rotation of a caprelative to the body 202. In some embodiments, the projections preventsuch rotation by mating with one or more corresponding projectionsprovided on a cap. It should be noted that in other embodiments thevalve body 202 does not include projections 206.

The valve 200 has an internal conduit, a first end of which connects tothe drain apertures 208 and a second end of which opens on to the end ofthe flange. A valve mechanism is provided in some embodiments which isoperable to change the valve from a closed configuration in which theconduit is blocked to a drain configuration in which the conduit is openand thus any liquid entering a drain aperture 208 may pass through theconduit and exit through the second end of the conduit and thus exit thefuel tank.

FIG. 2 b shows a plan view of the direct water drain valve of FIG. 2 a.As can be seen, the peripheral wall 222 of the flange 204 is furtherfrom the longitudinal axis of the body at some places than at others. Inthe illustrated embodiment, the flange 204 is oval in shape. However, inother embodiments the flange can be other non-circular shapes,preferably devoid of sharp features, so as to resist relative rotationbetween the body and the base of a fuel tank. For example the flangecould be hexagonal in shape. If the peripheral wall 222 is devoid ofsharp features it means that it is easier to form the correspondingrecess in the fuel tank body, which may be formed of composite materialwhich is difficult to form sharp features in.

The boss 216 comprises a disc shaped projection positioned concentricwith respect to the longitudinal axis of the body 202. The projections206 provided on the outer face of the valve body 202 are in theillustrated embodiment provided at equidistant positions around thecircumference of the upper circumferential wall 212. The valve body 202may be formed of a plastics material, such as PTFE, or any othersuitable material that is light-weight and non-ferrous, such asAluminium or a Titanium alloy.

The direct water drain valve 200 is arranged to be secured, in a fluidtight manner, to a surface such as a base of a fuel tank. The fuel tankhas an aperture formed or cut of corresponding dimensions to the lowercircumferential wall 210 of the valve body 202. Furthermore, a recess isformed or provided on the outside face of the fuel tank. The recesscorresponding in size and shape to the flange 204 such that the flangecan be received in the recess. Preferably, the flange is received in therecess so as to be in registration with the outside surface of the fueltank adjacent the recess. It is not necessary to provide a projection toprevent rotation between the valve body and the fuel tank because thenon-circular nature of the flange prevents such rotation. With thedirect water drain valve 200 pushed through the aperture in the fueltank such that the flange 204 is received within the recess, a nut 224can be passed over the first end of the body 202 and the nut rotatedsuch that its thread engages with the threaded part of the lowercircumferential wall 210 of the body 202. The nut 224 may be rotateduntil one of its axial faces presses against the upper face of the baseof the fuel tank. It will be appreciated that the combination of nut 224and threaded part of the lower circumferential wall 210 of the body 202enables the valve 200 to be fitted to structures of a range ofthicknesses. The length of the threaded part in the axial direction ofthe circumferential wall 210 provides flexibility as to how far alongthe length of the threaded part the nut 224 needs to travel to contact aface of the structure, so as to secure the valve 200 to the structure.In the illustrated embodiment, as shown in FIG. 2 c, once the nut isfully tightened the upper axial face of the nut is in registration withthe shoulder 214 of the body. Whilst in this embodiment a nut 224 isused to secure the body 202 to the fuel tank, the skilled person will beable to envisage other suitable ways of attaching the valve body 202 toa fuel tank in a fluid-tight manner, such as bonding.

In use, should a layer of water collect at the bottom of the fuel tankwithin which the valve 200 is disposed, a serviceman may operate thevalve mechanism to “open” the valve and upon doing so the collectedwater passes through drain apertures 208 through the internal conduitand exit the valve on the outside of the fuel tank. A serviceman maycontinue to hold the valve until fuel begins to flow from the valve atwhich time the valve may be closed.

Referring to FIGS. 3 a to 4, valve apparatus according to an embodimentof the invention is shown for converting a direct water 200 drain valveinto an indirect water drain valve. Valve apparatus includes a firstelement having an inner volume and a fluid transfer aperture for fluidto enter the inner volume, the valve apparatus being arranged to becoupled to the direct water drain valve such that at least some of theinner volume forms a substantially fluid-tight passageway between thefluid transfer aperture and the at least one drain conduit of the directwater drain valve.

The first element in the illustrated embodiment comprises a cap 300. Thecap 300 includes a generally cylindrical sidewall 302 closed at one endby a top face 304 and open at its second end. The second end of thesidewall 302 defines a shoulder portion 308 from which extends a skirt310. The skirt 310 has a larger diameter than the sidewall 302. It willbe appreciated that the cap 300 can other types of side wall or sidewalls, such as a straight side wall.

A fluid transfer aperture is formed through the sidewall 302 and is inthis embodiment surrounded by a spout 312 comprising a proximal pipeintegrally formed with a distal pipe of relatively larger diameter. Thedistal pipe 316 defines an opening 318 in fluid communication with thefluid transfer aperture. In other embodiments the spout 312 is composedof a straight pipe, which would be suitable for attachment to a rubberpipe capable of radial distension, the pipe possibly having a ridgedouter circumferential area for retaining a tube thereon. In anotherembodiment the cap 300 does not include a spout 312 and the fluidtransfer aperture is arranged to retain a tube in a sealed manner. Forexample, the fluid transfer aperture can be interfaced with a tube oflarger diameter capable of radial distension so as to expand and fillthe fluid transfer aperture.

In some embodiments, a connection aperture 320 may be formed through thetop surface for a screw or other fixing means to pass through to securethe cap to a direct drain valve. In some cases, the connection aperture320 may be surrounded by a strengthening ring 306, the function of whichwill be apparent. It will be appreciated that whilst the connectionaperture 320 is advantageous if the cap 300 is to be connected to thevalve body 202 using, for example, a screw, in other embodiments the cap300 does not include a connection aperture 320 or strengthening ring306.

The cap may be formed of a plastics material, such as HDPE or any othersuitable material that is light-weight and non-ferrous, such asAluminium or a Titanium alloy.

FIG. 3 b shows the inside of the cap 300. The cap 300 has an innervolume. In some embodiments, one or more projections 322 are providedaround the inner circumferential wall of the cap so as to correspond tothe projections 206 provided on the outer face of the valve body 202such that the two sets of projections 206, 322 mate and form a rotationlimiter to limit rotation therebetween. When the cap 300 is connected tothe valve body 202 via a suitable connection means, the projections 206provided on the outer face of the valve body 202 and projections 322provided on the inner face of the cap 300 engage to limit the amountthat the cap 300 can rotate relative to the body 202. This enables thecap to be placed upon the direct water drain valve in one of a number ofparticular orientations and prevent further substantial rotationtherebetween. It will be apparent that this enables the spout 312 to beset to a particular orientation, such as a facing towards a remote areawhich it is desirable to drain. Whilst the illustrated embodimentincludes projections 206 provided on the outer face of the valve body202 to form an interlock with projections 322 provided on the inner faceof the cap 300 it will be noted that there are other ways forcontrolling the orientation of the cap relative to the valve body. Anexample is a friction inducing member which could be a material providedbetween the valve body and the cap or could be provided by the relativedimensions i.e. the cap being of similar or fractionally smallerdiameter than the valve body. In some embodiments the projections 322and provided at a different location on the cap 300 and in otherembodiments the cap 300 does not include the projections 322.

FIG. 4 shows means by which the cap 300 may be connected to the valvebody 202 according to an embodiment of the present invention. A slottednut 400 has peripheral faces 404, a threaded inside face 406 and acylindrical groove 402 formed through a first axial face 408 thereof.The nut 400 may have a second groove (not shown) in the opposing axialface to the groove 402. The second groove is arranged to receive asealing ring for providing a substantially fluid-tight seal between therespective face of the nut 400 and an inside surface of a fuel tankwall. The purpose of the slotted nut 400 is to interface with the cap300 such that a fluid-tight passageway is formed between the fluidtransfer aperture 313 in the cap 300 and the conduit in the valve 200.Whilst this is an advantageous embodiment, due in part to the fact thatit makes use of an already exiting part (the nut) which is used toconnect the valve body 202 to the fuel tank, in other embodimentsdifferent means are provided by which a fluid-tight passageway is formedbetween the fluid transfer aperture 313 in the cap 300 and the conduitin the valve 200. For example, the cap 300 could have an inwardlyextending skirt having an inner diameter which is smaller than the outerdiameter of the valve body, such that the inwardly extending skirt couldbe forced over the valve body, thereby creating a substantiallyfluid-tight seal between them. In another embodiment, the open end ofthe cap 300 is elastic and cab be distended and placed over the valvebody 202. When released, the cap 300 contracts to form a sealingconnection between itself and the wall of the valve body 202. In anotherembodiment the cap may be arranged to be bonded to the valve body, forexample by glue.

FIG. 5 shows an indirect water drain valve interfaced with a fuel tankwall 502. The wall 502 will typically be a base wall. The indirect waterdrain valve 500 has been secured to the base of the fuel tank 502 in asimilar manner to that described above for connection of a direct waterdrain valve 200. However, rather than a standard nut, a slotted nut 400is used to secure the valve body to the base of the fuel tank 504. Ascan be seen, the flange 204 of the valve body 202 is within thecorresponding recess 502 formed through the outside surface 506 of thefuel tank base 502 and in registration therewith. By placing the cap 300over the part of the valve body projecting through the base of the tank502 into the inside of the tank, a seal is formed by the side wall 302of the cap 300 being received within the slot 402 and this sealcontributes to a substantially fluid tight passageway between the fluidtransfer aperture 313 and the conduit 508 within the valve body. A pipeor duct (not shown) may have a first end connected to the spout and asecond end located at an area that is desirable to drain water from. Insome embodiments the cap has a plurality of fluid transfer apertures313, with or without spouts.

The fluid transfer aperture 313 is provided through the sidewall 302 ofthe cap 300. In the illustrated embodiment the fluid transfer aperture313 is approximately mid way up the sidewall 302. However, in otherembodiments the fluid transfer aperture may be provided below thehalfway point of the cap and in a preferred embodiment it is locatedadjacent to the slotted nut 400. The skilled person will appreciatethat, generally, the closer a fluid transfer aperture and spout 312 areto the top surface of the base 502, the less pressure is required totransfer fluid, such as water, from the tank to the fluid transferaperture 313. Consequently, by providing the fluid transfer aperture onthe sidewall of the cap, rather than for example on the top surface ofthe cap, water can be drained from the tank with less aviation fuel inthe tank than is possible using prior art indirect drain valves. Theindirect water drain valve according to some embodiments of the presentinvention results in water being drainable from a fuel tank with 50%less fuel in it, compared to some prior art indirect water drain valves.Preferably, the fluid transfer aperture is provided between the flange204 and halfway between the flange 204 and the first end of the valvebody 202. In one embodiment, the cap is configured such that the fluidtransfer aperture is adjacent a general plane of the dividing structure.

In use, a user may operate the valve mechanism 510 to open the valvemember within the conduit 508, thereby allowing water to pass to theoutlet 512. The pressure acting on the top surface of the water at thebottom of the fuel tank by aviation fuel above it causes water to movefrom the drainage area through the duct (not shown) and through thefluid transfer aperture 313, into conduit 508 and out via outlet 512.Once the water has been drained from the tank the valve mechanism 510 isoperated to close the valve by sealing conduit 508. The cap 300 andmeans by which it is sealed to the valve body 202 provide a watertightpassageway between the conduit and fluid transfer aperture meaning thatsubstantially no fluid from an area adjacent and outside the cap 300 canexit via the conduit and also any fluid, such as water, entering thefluid volume 317 cannot escape to mix with fluid adjacent and outsidethe cap 300.

In some embodiments a seal 518 is provided between the skirt 310 andslot 402 and/or a seal 514 is provided between the slotted nut 400 andbase of the fuel tank 502. The seal 518 between the skirt and the slotmay be a fillet seal or other suitable sealing means. In someembodiments a seal 516 is provided between the slotted nut 400 and valvebody.

Therefore the valve apparatus 300 according to a further embodiment ofthe present invention enables an existing direct drain valve 200 to beconverted into an indirect drain valve. The apparatus includes a firstelement 300 and is arranged to be coupled to the existing direct drainvalve body 202 so as to create a substantially fluid tight passage waybetween a fluid transfer aperture 313 through the first element and adrain conduit 508 of the valve. The passageway includes at least some ofthe inner volume of the first element 300. Thus, because a substantiallyfluid tight passage way is formed between the fluid transfer aperture313 and drain conduit 508 of the valve 200, any fluid entering the innervolume of the first element 300 through the fluid transfer aperture 313can be drawn or forced to exit the valve 200 through the drain conduit508.

Referring to FIGS. 6 a to 6 c, a device 600 is shown according to anembodiment of the invention. The device 600 is arranged to be attachedto a structure 606, such as a wall of a fuel tank. The device 600 may bea water drain valve, or other component, which is arranged to be fixedto a structure with a limited amount of freedom to rotate about thestructure 606. In some embodiments, the device 600 is a direct waterdrain valve according to an embodiment of the invention as describedabove. The device 600 includes a generally cylindrical body 602 a firstend of which is arranged to pass through a corresponding aperture in thestructure 606 to which the device 600 is to be attached. A second end ofthe body 602 defines or is connected to a flange 604. The flange 604projects radially from the second end of the body 602. The flange 604has generally planar axial faces and a peripheral wall. When viewed froma plane parallel to a planar axial face, as shown in FIG. 6 c, theflange 604 is non-circular i.e. the peripheral wall does not define acircular path. As can be seen, the peripheral wall of the flange 604 isfurther from the longitudinal axis of the body 602 at some places thanat others. In the illustrated embodiment, the flange 604 is oval inshape and has at least one oval shaped face. However, in otherembodiments the flange can be other non-circular shapes, preferablydevoid of sharp features, so as to resist relative rotation between thebody and the base of a fuel tank. For example the flange could behexagonal in shape. If the peripheral wall is devoid of sharp featuresit means that it is easier to form the corresponding recess in the fueltank body, which may be formed of composite material which is difficultto form sharp features in.

The flange is arranged to be received within a corresponding recessformed in a face of the structure 606 to which the device 600 is to beattached. The recess in the structure 606 is coincident with theaperture corresponding to the body 602. The flange is received withinthe recess such that the axial face of the flange 604 which faces awayfrom the body 602 is in registration with the corresponding face of thestructure 606. However, it will be appreciated that other configurationsmay be appropriate, such as the axial face of the flange 604 which facesaway from the body 602 not being in registration with the correspondingface of the structure 606. Due to the flange being non-circular,rotation of the flange 604 and thus the body 602 relative to thestructure 606 is limited to that permitted by “play” between the flangeand recess.

Thus the device cannot rotate freely about the structure because theflange is non-circular and rotation causes a part of the flange tocontact a sidewall of the recess so as to prevent further rotation inthat direction. In the illustrated embodiment, part of the perimeter ofthe flange is located further from the longitudinal axis of the bodythan another part. Thus, providing the recess has a perimeter wallhaving at least one part which is at a distance, from the longitudinalaxis of the body, greater than the shortest distance between thelongitudinal axis of the body and the flange and less than the largestdistance between the longitudinal axis of the body and the flange, itwill result in rotation of the device being restricted.

It is therefore not necessary to provide a projection or the like toprevent rotation between the device 600 and the structure 606 becausethe non-circular nature of the flange 604 prevents such rotation. Withthe body 602 of the device 600 pushed through the corresponding aperturein the structure 606 such that the flange 604 is received within therecess, a nut can be passed over the first end of the body 602 and thenut rotated such that its thread engages with a threaded part of thebody 602. Whilst in this embodiment a nut is used to secure the body 602to the structure 606, the skilled person will be able to envisage othersuitable ways of attaching the body 602 to a structure 606 in afluid-tight manner, such as bonding.

1. A device arranged to be attached to a structure, the structure havinga recess formed in a surface thereof providing a recessed surface, andan aperture formed through the recessed surface, the device including abody arranged to be received in the aperture and a non-circular flangearranged to be received in the recess such that the non-circularconfiguration of the flange in combination with the recess limitsrotation between the device and the structure.
 2. A device according toclaim 1, wherein the flange has an oval shaped perimeter.
 3. A deviceaccording to claim 1, wherein the device comprises a water drain valveincluding: a body arranged to extend through an outer wall of a fluidcontaining vessel the body having a conduit for providing an outlet fromthe fluid vessel; and valve apparatus including a first element having afluid volume and a fluid transfer aperture for fluid to enter the fluidvolume and being arranged to be coupled to the valve body such that atleast some of the inner volume forms a substantially fluid-tightpassageway between the fluid transfer aperture and the conduit.